[PATCH 3/3] clk: shmobile: Add R8A7790 clocks support
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Nov 6 07:56:18 EST 2013
Hi Simon,
On Wednesday 06 November 2013 16:18:09 Simon Horman wrote:
> On Tue, Oct 29, 2013 at 03:55:11PM +0100, Laurent Pinchart wrote:
> > The R8A7790 has several clocks that are too custom to be supported in a
> > generic driver. Those clocks can be divided in two categories:
> >
> > - Fixed rate clocks with multiplier and divisor set according to boot
> > mode configuration
> >
> > - Custom divider clocks with SoC-specific divider values
> >
> > This driver supports both.
> >
> > Signed-off-by: Laurent Pinchart
> > <laurent.pinchart+renesas at ideasonboard.com>
> > ---
> >
> > .../bindings/clock/renesas,r8a7790-cpg-clocks.txt | 26 +++
> > drivers/clk/shmobile/Makefile | 1 +
> > drivers/clk/shmobile/clk-r8a7790.c | 176 ++++++++++++++++
> > include/dt-bindings/clock/r8a7790-clock.h | 10 ++
> > include/linux/clk/shmobile.h | 19 +++
> > 5 files changed, 232 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/clock/renesas,r8a7790-cpg-clocks.txt
> > create mode 100644 drivers/clk/shmobile/clk-r8a7790.c
> > create mode 100644 include/linux/clk/shmobile.h
> >
> > diff --git
> > a/Documentation/devicetree/bindings/clock/renesas,r8a7790-cpg-clocks.txt
> > b/Documentation/devicetree/bindings/clock/renesas,r8a7790-cpg-clocks.txt
> > new file mode 100644
> > index 0000000..d889917
> > --- /dev/null
> > +++
> > b/Documentation/devicetree/bindings/clock/renesas,r8a7790-cpg-clocks.txt
> > @@ -0,0 +1,26 @@
> > +* Renesas R8A7790 Clock Pulse Generator (CPG)
> > +
> > +The CPG generates core clocks for the R8A7790. It includes three PLLs and
> > +several fixed ratio dividers.
> > +
> > +Required Properties:
> > +
> > + - compatible: Must be "renesas,r8a7790-cpg-clocks"
> > + - reg: Base address and length of the memory resource used by the CPG
> > + - clocks: Reference to the parent clock
> > + - #clock-cells: Must be 1
> > + - clock-output-names: The name of the clocks, must be "main", "pll1",
>
> s/The name/The names/
Will fix, thank you.
> > + "pll3", "lb", "qspi", "sdh", "sd0", "sd1".
> > +
> > +
> > +Example
> > +-------
> > +
> > + cpg_clocks: cpg_clocks {
> > + compatible = "renesas,r8a7790-cpg-clocks";
> > + reg = <0 0xe6150000 0 0x1000>;
> > + clocks = <&extal_clk>;
> > + #clock-cells = <1>;
> > + clock-output-names = "main", "pll1", "pll3", "lb",
> > + "qspi", "sdh", "sd0", "sd1";
> > + };
>
> I wonder if it makes sense to craft a more generic bindings document.
>
> I am currently working on clock support for the r8a7779 (H1) based
> on this patch series and I expect the bindings to end up being
> more or less the same.
>
> I expect there to be similar support to be added for many other renesas SoCs
> over time.
That's a good idea. I'll gladly review patches :-)
> > diff --git a/drivers/clk/shmobile/Makefile b/drivers/clk/shmobile/Makefile
> > index 3275c78..949f29e 100644
> > --- a/drivers/clk/shmobile/Makefile
> > +++ b/drivers/clk/shmobile/Makefile
> > @@ -1,4 +1,5 @@
> > obj-$(CONFIG_ARCH_EMEV2) += clk-emev2.o
> > +obj-$(CONFIG_ARCH_R8A7790) += clk-r8a7790.o
> > obj-$(CONFIG_ARCH_SHMOBILE_MULTI) += clk-div6.o
> > obj-$(CONFIG_ARCH_SHMOBILE_MULTI) += clk-mstp.o
> > diff --git a/drivers/clk/shmobile/clk-r8a7790.c
> > b/drivers/clk/shmobile/clk-r8a7790.c new file mode 100644
> > index 0000000..2e76638
> > --- /dev/null
> > +++ b/drivers/clk/shmobile/clk-r8a7790.c
> > @@ -0,0 +1,176 @@
> > +/*
> > + * r8a7790 Core CPG Clocks
> > + *
> > + * Copyright (C) 2013 Ideas On Board SPRL
> > + *
> > + * Contact: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; version 2 of the License.
> > + */
> > +
> > +#include <linux/clk-provider.h>
> > +#include <linux/clkdev.h>
> > +#include <linux/clk/shmobile.h>
> > +#include <linux/init.h>
> > +#include <linux/kernel.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/spinlock.h>
> > +
> > +#include <dt-bindings/clock/r8a7790-clock.h>
> > +
> > +#define CPG_NUM_CLOCKS (R8A7790_CLK_SD1 + 1)
>
> Perhaps R8A7790_NUM_CLOCKS in r8a7790-clock.h would be nicer.
Good question. The dt-bindings/ headers are primarly meant to store macros
used by .dts files and (possibly) shared with C code. Given that
R8A7790_NUM_CLOCKS isn't used by .dts files I'm not sure it would belong to
that header.
> > +
> > +struct r8a7790_cpg {
> > + struct clk_onecell_data data;
> > + spinlock_t lock;
> > + void __iomem *reg;
> > +};
> > +
> > +/*
> > + * MD EXTAL PLL0 PLL1 PLL3
> > + * 14 13 19 (MHz) *1 *1
> > + *---------------------------------------------------
> > + * 0 0 0 15 x 1 x172/2 x208/2 x106
> > + * 0 0 1 15 x 1 x172/2 x208/2 x88
> > + * 0 1 0 20 x 1 x130/2 x156/2 x80
> > + * 0 1 1 20 x 1 x130/2 x156/2 x66
> > + * 1 0 0 26 / 2 x200/2 x240/2 x122
> > + * 1 0 1 26 / 2 x200/2 x240/2 x102
> > + * 1 1 0 30 / 2 x172/2 x208/2 x106
> > + * 1 1 1 30 / 2 x172/2 x208/2 x88
> > + *
> > + * *1 : Table 7.6 indicates VCO ouput (PLLx = VCO/2)
> > + */
> > +#define CPG_PLL_CONFIG_INDEX(md) ((((md) & BIT(14)) >> 12) | \
> > + (((md) & BIT(13)) >> 12) | \
> > + (((md) & BIT(19)) >> 19))
> > +struct cpg_pll_config {
> > + unsigned int extal_div;
> > + unsigned int pll1_mult;
> > + unsigned int pll3_mult;
> > +};
> > +
> > +static const struct cpg_pll_config cpg_pll_configs[8] = {
> > + { 1, 208, 106 }, { 1, 208, 88 }, { 1, 156, 80 }, { 1, 156, 66 },
> > + { 2, 240, 122 }, { 2, 240, 102 }, { 2, 208, 106 }, { 2, 208, 88 },
> > +};
> > +
> > +/* SDHI divisors */
> > +static const struct clk_div_table cpg_sdh_div_table[] = {
> > + { 0, 2 }, { 1, 3 }, { 2, 4 }, { 3, 6 },
> > + { 4, 8 }, { 5, 12 }, { 6, 16 }, { 7, 18 },
> > + { 8, 24 }, { 10, 36 }, { 11, 48 }, { 0, 0 },
> > +};
> > +
> > +static const struct clk_div_table cpg_sd01_div_table[] = {
> > + { 5, 12 }, { 6, 16 }, { 7, 18 }, { 8, 24 },
> > + { 10, 36 }, { 11, 48 }, { 12, 10 }, { 0, 0 },
> > +};
>
> Can any or all of the above three constants be __initconst?
Not the clk_div_table arrays, as they're stored in the divider clock structure
internally and used at runtime. The cpg_pll_configs array, however, can. I'll
fix that.
> > +
> > +static u32 cpg_mode __initdata;
> > +
> > +#define CPG_SDCKCR 0x00000074
> > +
> > +static void __init r8a7790_cpg_clocks_init(struct device_node *np)
> > +{
> > + const struct cpg_pll_config *config;
> > + struct r8a7790_cpg *cpg;
> > + struct clk **clks;
> > + unsigned int i;
> > +
> > + cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
>
> Nit: s/sizeof(*cpg)/sizeof *cpg/, sizeof is an operator.
That's what I do in my non-kernel code, but the kernel coding style uses ().
It took me a bit of time to get used to it :-)
> > + clks = kzalloc(CPG_NUM_CLOCKS * sizeof(*clks), GFP_KERNEL);
> > + if (cpg == NULL || clks == NULL) {
> > + kfree(clks);
> > + kfree(cpg);
> > + pr_err("%s: failed to allocate cpg\n", __func__);
> > + return;
> > + }
> > +
> > + spin_lock_init(&cpg->lock);
> > +
> > + cpg->data.clks = clks;
> > + cpg->data.clk_num = CPG_NUM_CLOCKS;
> > +
> > + cpg->reg = of_iomap(np, 0);
> > + if (WARN_ON(cpg->reg == NULL)) {
> > + kfree(cpg->data.clks);
> > + kfree(cpg);
> > + return;
> > + }
>
> Perhaps this error checking could be merged with that of cpg and clks?
Morimoto-san has already pointed-out that issue. Here was my answer, your
opinion would be appreciated.
Given that a failure to allocate memory or ioremap registers will lead to a
boot failure, I wonder whether we couldn't just remove the kfree() calls and
leak memory. Is there a point in cleaning up behind us if the system will no
boot due to missing core clocks anyway ?
> > +
> > + config = &cpg_pll_configs[CPG_PLL_CONFIG_INDEX(cpg_mode)];
> > +
> > + for (i = 0; i < CPG_NUM_CLOCKS; ++i) {
> > + const struct clk_div_table *table = NULL;
> > + const char *parent_name = "main";
> > + const char *name;
> > + unsigned int shift;
> > + unsigned int mult = 1;
> > + unsigned int div = 1;
> > + struct clk *clk;
> > +
> > + of_property_read_string_index(np, "clock-output-names", i,
> > + &name);
> > +
> > + switch (i) {
> > + case R8A7790_CLK_MAIN:
> > + parent_name = of_clk_get_parent_name(np, 0);
> > + div = config->extal_div;
> > + break;
> > + case R8A7790_CLK_PLL1:
> > + mult = config->pll1_mult / 2;
> > + break;
> > + case R8A7790_CLK_PLL3:
> > + mult = config->pll3_mult;
> > + break;
> > + case R8A7790_CLK_LB:
> > + div = cpg_mode & BIT(18) ? 36 : 24;
> > + break;
> > + case R8A7790_CLK_QSPI:
> > + div = (cpg_mode & (BIT(3) | BIT(2) | BIT(1))) == BIT(2)
> > + ? 16 : 20;
> > + break;
> > + case R8A7790_CLK_SDH:
> > + table = cpg_sdh_div_table;
> > + shift = 8;
> > + break;
> > + case R8A7790_CLK_SD0:
> > + table = cpg_sd01_div_table;
> > + shift = 4;
> > + break;
> > + case R8A7790_CLK_SD1:
> > + table = cpg_sd01_div_table;
> > + shift = 0;
> > + break;
> > + }
>
> I wonder if it would be good to and skip the portions below if the switch
> statement hits a default: case.
Yes, but that would be a bug in the driver, as all cases should be handled :-)
> Also, if i was an enum type then I think the C compiler would warn
> about any missing cases. That might be nice too.
It would be, but the DT compiler doesn't support enums, so we're stuck with
#define's if we want to share them between .dts and C files.
> > +
> > + if (!table)
> > + clk = clk_register_fixed_factor(NULL, name, parent_name,
> > + 0, mult, div);
> > + else
> > + clk = clk_register_divider_table(NULL, name,
> > + parent_name, 0,
> > + cpg->reg + CPG_SDCKCR,
> > + shift, 4, 0, table,
> > + &cpg->lock);
> > +
> > + if (IS_ERR(clk))
> > + pr_err("%s: failed to register %s %s clock (%ld)\n",
> > + __func__, np->name, name, PTR_ERR(clk));
> > + }
> > +
> > + of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
> > +}
> > +CLK_OF_DECLARE(r8a7790_cpg_clks, "renesas,r8a7790-cpg-clocks",
> > + r8a7790_cpg_clocks_init);
> > +
> > +void __init r8a7790_clocks_init(u32 mode)
> > +{
> > + cpg_mode = mode;
> > +
> > + of_clk_init(NULL);
> > +}
> > diff --git a/include/dt-bindings/clock/r8a7790-clock.h
> > b/include/dt-bindings/clock/r8a7790-clock.h index 19f2b48..f0ed742 100644
> > --- a/include/dt-bindings/clock/r8a7790-clock.h
> > +++ b/include/dt-bindings/clock/r8a7790-clock.h
> > @@ -10,6 +10,16 @@
> >
> > #ifndef __DT_BINDINGS_CLOCK_R8A7790_H__
> > #define __DT_BINDINGS_CLOCK_R8A7790_H__
> >
> > +/* CPG */
> > +#define R8A7790_CLK_MAIN 0
> > +#define R8A7790_CLK_PLL1 1
> > +#define R8A7790_CLK_PLL3 2
> > +#define R8A7790_CLK_LB 3
> > +#define R8A7790_CLK_QSPI 4
> > +#define R8A7790_CLK_SDH 5
> > +#define R8A7790_CLK_SD0 6
> > +#define R8A7790_CLK_SD1 7
> > +
> >
> > /* MSTP1 */
> > #define R8A7790_CLK_CMT0 20
> >
> > diff --git a/include/linux/clk/shmobile.h b/include/linux/clk/shmobile.h
> > new file mode 100644
> > index 0000000..b090855
> > --- /dev/null
> > +++ b/include/linux/clk/shmobile.h
> > @@ -0,0 +1,19 @@
> > +/*
> > + * Copyright 2013 Ideas On Board SPRL
> > + *
> > + * Contact: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + */
> > +
> > +#ifndef __LINUX_CLK_SHMOBILE_H_
> > +#define __LINUX_CLK_SHMOBILE_H_
> > +
> > +#include <linux/types.h>
> > +
> > +void r8a7790_clocks_init(u32 mode);
> > +
> > +#endif
--
Regards,
Laurent Pinchart
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